a. Field of the Invention
The invention relates to a heat dissipation module, and, more particularly, to a heat dissipation module suitable for use in a projection apparatus.
b. Description of the Related Art
Taiwan patent publication no. 201022826 discloses a conventional heat dissipation module as shown in FIG. 4. When a lamp wick 102 emits light, mercury vapor of the lamp wick 102 rises and condenses to give out heat. Accordingly, a connecting line of a hot spot S and the center of the lamp wick 102 is substantially parallel to the direction of gravity G. Therefore, no matter where the lamp wick 102 is rotated, the connecting line of the hot spot S and the center of the lamp wick 102 is kept to be substantially parallel to the direction of gravity G. However, when a projection apparatus is inclined, the lamp wick 102, a lamp cover 104 and a fan 106 may rotate to form an angle α with respect to a horizontal plane H. In that case, as shown in FIG. 4, an air flow induced by the fan 106 and flowing through the lamp wick 102 flows in a non-parallel direction instead of a parallel direction with respect to the horizontal plane H. Therefore, the air flow is not efficiently directed to the hot spot S of the lamp wick 102, and the speed of the air flow flowing in a non-parallel direction is slower compared with a parallel manner to result in low cooling efficiency of the fan 106. The heat dissipation module 100 shown in FIG. 4 has an adjustment mechanism 108. The adjustment mechanism 108 is used to force air-guiding modules 112 and 114 to rotate about the lamp cover 104 to therefore change air-guiding angles of the air-guiding modules 112 and 114. In that case, the air flow is allowed to flow through the lamp wick 102 in a direction parallel to the horizontal plane H to achieve high cooling efficiency. However, according to the above design, the air-guiding angles of the air-guiding modules 112 and 114 are manually adjusted to result in inconvenient operations and a limited extent of adjusting effects. Further, Taiwan patent publication no. 200905365 discloses a heat dissipation module. In the heat dissipation module, when a projection apparatus is disposed on a slant, an air guiding structure is manually adjusted to enable an air flow to flow in a horizontal direction to achieve high cooling efficiency. Besides, US patent publication no. 20080231812 discloses a cooling device having two fans to cool down a lamp, and a gravity sensor is used to detect a current orientation of the projection apparatus to modulate the amount of an air flow flowing through the lamp. In addition, US patent publication no. 20080218050 discloses a design of controlling the flow direction of cooling air by rotating a movable collar. China patent no. 100385607 discloses a design of inducing an air flow by a fan and delivering the air flow to the hot spot of a lamp by pipes. Taiwan patent no. 1261858 discloses a design of introducing an air flow into a lamp and exhausting hot air out of the lamp by a fan disposed back the lamp to cool down the lamp. Taiwan patent no. M278917 discloses a cooling design using two blowers. An air flow is induced by one blower to flow through a lamp wick, and an air flow is induced by the other blower to flow through a metal piece in front of the lamp wick and lead wires of the lamp.
Though the above designs may cool down the lamp to a certain extent, they are not designed to ensure the air flow induced by a fan and the air flow continually flows through the hot spot of a lamp. Therefore, the cooling efficiency fails to be further improved.